1. We also refer to the recent collection of lecture notes edited by Visintin (1994b).
2. In the literature, this operator is often referred to as the Ishlinskii operator or the Ishlinshii transducer, see Krasnoselskii-Pokrovskii (1989). We prefer to name it after Prandtl whose paper appeared more than a decade before Ishlinskii’s who studied this operator in the early forties.
3. For an account of Preisach’s life, see Vajda-Della Torre (1995).
4. See Krasnoselskii-Pokrovskii (1989), Section 34.2.
5. See Krasnoselskii-Pokrovskii (1989), Section 2.